Displaying 20 results from an estimated 47 matches for "_q_pending_mask".
2014 Jun 18
2
[PATCH 05/11] qspinlock: Optimize for smaller NR_CPUS
Il 15/06/2014 14:47, Peter Zijlstra ha scritto:
>
> - for (;;) {
> - new = (val & ~_Q_PENDING_MASK) | _Q_LOCKED_VAL;
> -
> - old = atomic_cmpxchg(&lock->val, val, new);
> - if (old == val)
> - break;
> -
> - val = old;
> - }
> + clear_pending_set_locked(lock, val);
> return;
Might as well add clear_pending_set_locked already in patch 3.
Paolo
2014 Jun 18
2
[PATCH 05/11] qspinlock: Optimize for smaller NR_CPUS
Il 15/06/2014 14:47, Peter Zijlstra ha scritto:
>
> - for (;;) {
> - new = (val & ~_Q_PENDING_MASK) | _Q_LOCKED_VAL;
> -
> - old = atomic_cmpxchg(&lock->val, val, new);
> - if (old == val)
> - break;
> -
> - val = old;
> - }
> + clear_pending_set_locked(lock, val);
> return;
Might as well add clear_pending_set_locked already in patch 3.
Paolo
2014 Jul 07
2
[PATCH 05/11] qspinlock: Optimize for smaller NR_CPUS
Il 07/07/2014 16:35, Peter Zijlstra ha scritto:
> On Wed, Jun 18, 2014 at 01:39:52PM +0200, Paolo Bonzini wrote:
>> Il 15/06/2014 14:47, Peter Zijlstra ha scritto:
>>>
>>> - for (;;) {
>>> - new = (val & ~_Q_PENDING_MASK) | _Q_LOCKED_VAL;
>>> -
>>> - old = atomic_cmpxchg(&lock->val, val, new);
>>> - if (old == val)
>>> - break;
>>> -
>>> - val = old;
>>> - }
>>> + clear_pending_set_locked(lock, val);
>>> return;
>>
&...
2014 Jul 07
2
[PATCH 05/11] qspinlock: Optimize for smaller NR_CPUS
Il 07/07/2014 16:35, Peter Zijlstra ha scritto:
> On Wed, Jun 18, 2014 at 01:39:52PM +0200, Paolo Bonzini wrote:
>> Il 15/06/2014 14:47, Peter Zijlstra ha scritto:
>>>
>>> - for (;;) {
>>> - new = (val & ~_Q_PENDING_MASK) | _Q_LOCKED_VAL;
>>> -
>>> - old = atomic_cmpxchg(&lock->val, val, new);
>>> - if (old == val)
>>> - break;
>>> -
>>> - val = old;
>>> - }
>>> + clear_pending_set_locked(lock, val);
>>> return;
>>
&...
2014 Jun 15
0
[PATCH 05/11] qspinlock: Optimize for smaller NR_CPUS
...* 9-10: tail index
@@ -50,7 +58,11 @@ typedef struct qspinlock {
#define _Q_LOCKED_MASK _Q_SET_MASK(LOCKED)
#define _Q_PENDING_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
+#if CONFIG_NR_CPUS < (1U << 14)
+#define _Q_PENDING_BITS 8
+#else
#define _Q_PENDING_BITS 1
+#endif
#define _Q_PENDING_MASK _Q_SET_MASK(PENDING)
#define _Q_TAIL_IDX_OFFSET (_Q_PENDING_OFFSET + _Q_PENDING_BITS)
@@ -61,6 +73,7 @@ typedef struct qspinlock {
#define _Q_TAIL_CPU_BITS (32 - _Q_TAIL_CPU_OFFSET)
#define _Q_TAIL_CPU_MASK _Q_SET_MASK(TAIL_CPU)
+#define _Q_TAIL_OFFSET _Q_TAIL_IDX_OFFSET
#define _Q_TAIL_M...
2014 Apr 17
0
[PATCH v9 05/19] qspinlock: Optimize for smaller NR_CPUS
...* 9-10: tail index
@@ -50,7 +58,11 @@ typedef struct qspinlock {
#define _Q_LOCKED_MASK _Q_SET_MASK(LOCKED)
#define _Q_PENDING_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
+#if CONFIG_NR_CPUS < (1U << 14)
+#define _Q_PENDING_BITS 8
+#else
#define _Q_PENDING_BITS 1
+#endif
#define _Q_PENDING_MASK _Q_SET_MASK(PENDING)
#define _Q_TAIL_IDX_OFFSET (_Q_PENDING_OFFSET + _Q_PENDING_BITS)
@@ -61,6 +73,7 @@ typedef struct qspinlock {
#define _Q_TAIL_CPU_BITS (32 - _Q_TAIL_CPU_OFFSET)
#define _Q_TAIL_CPU_MASK _Q_SET_MASK(TAIL_CPU)
+#define _Q_TAIL_OFFSET _Q_TAIL_IDX_OFFSET
#define _Q_TAIL_M...
2014 Jun 15
0
[PATCH 03/11] qspinlock: Add pending bit
...ype ## _OFFSET)
@@ -48,7 +49,11 @@ typedef struct qspinlock {
#define _Q_LOCKED_BITS 8
#define _Q_LOCKED_MASK _Q_SET_MASK(LOCKED)
-#define _Q_TAIL_IDX_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
+#define _Q_PENDING_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
+#define _Q_PENDING_BITS 1
+#define _Q_PENDING_MASK _Q_SET_MASK(PENDING)
+
+#define _Q_TAIL_IDX_OFFSET (_Q_PENDING_OFFSET + _Q_PENDING_BITS)
#define _Q_TAIL_IDX_BITS 2
#define _Q_TAIL_IDX_MASK _Q_SET_MASK(TAIL_IDX)
@@ -57,5 +62,6 @@ typedef struct qspinlock {
#define _Q_TAIL_CPU_MASK _Q_SET_MASK(TAIL_CPU)
#define _Q_LOCKED_VAL (1U <<...
2014 Apr 17
0
[PATCH v9 03/19] qspinlock: Add pending bit
...ype ## _OFFSET)
@@ -48,7 +49,11 @@ typedef struct qspinlock {
#define _Q_LOCKED_BITS 8
#define _Q_LOCKED_MASK _Q_SET_MASK(LOCKED)
-#define _Q_TAIL_IDX_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
+#define _Q_PENDING_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
+#define _Q_PENDING_BITS 1
+#define _Q_PENDING_MASK _Q_SET_MASK(PENDING)
+
+#define _Q_TAIL_IDX_OFFSET (_Q_PENDING_OFFSET + _Q_PENDING_BITS)
#define _Q_TAIL_IDX_BITS 2
#define _Q_TAIL_IDX_MASK _Q_SET_MASK(TAIL_IDX)
@@ -57,5 +62,6 @@ typedef struct qspinlock {
#define _Q_TAIL_CPU_MASK _Q_SET_MASK(TAIL_CPU)
#define _Q_LOCKED_VAL (1U <<...
2014 May 21
0
[RFC 08/07] qspinlock: integrate pending bit into queue
...al;
+ // optimizer might produce the same code if we use *pval directly
+
+ // we could use 'if' and a xchg that touches only the pending bit to
+ // save some cycles at the price of a longer line cutting window
+ // (and I think it would bug without changing the rest)
+ while (!(val & (_Q_PENDING_MASK | _Q_TAIL_MASK))) {
+ old = atomic_cmpxchg(&lock->val, val, val | _Q_PENDING_MASK);
+ if (old == val) {
+ *pval = val | _Q_PENDING_MASK;
+ return 1;
+ }
+ val = old;
+ }
+ *pval = val;
+ return 0;
+}
+
+// here
+static inline void set_pending(struct qspinlock *lock, u8 pending)
+{
+...
2014 Jun 18
1
[PATCH 05/11] qspinlock: Optimize for smaller NR_CPUS
...def struct qspinlock {
> #define _Q_LOCKED_MASK _Q_SET_MASK(LOCKED)
>
> #define _Q_PENDING_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
> +#if CONFIG_NR_CPUS < (1U << 14)
> +#define _Q_PENDING_BITS 8
> +#else
> #define _Q_PENDING_BITS 1
> +#endif
> #define _Q_PENDING_MASK _Q_SET_MASK(PENDING)
>
> #define _Q_TAIL_IDX_OFFSET (_Q_PENDING_OFFSET + _Q_PENDING_BITS)
> @@ -61,6 +73,7 @@ typedef struct qspinlock {
> #define _Q_TAIL_CPU_BITS (32 - _Q_TAIL_CPU_OFFSET)
> #define _Q_TAIL_CPU_MASK _Q_SET_MASK(TAIL_CPU)
>
> +#define _Q_TAIL_OFFSET _Q...
2014 Jun 18
1
[PATCH 05/11] qspinlock: Optimize for smaller NR_CPUS
...def struct qspinlock {
> #define _Q_LOCKED_MASK _Q_SET_MASK(LOCKED)
>
> #define _Q_PENDING_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
> +#if CONFIG_NR_CPUS < (1U << 14)
> +#define _Q_PENDING_BITS 8
> +#else
> #define _Q_PENDING_BITS 1
> +#endif
> #define _Q_PENDING_MASK _Q_SET_MASK(PENDING)
>
> #define _Q_TAIL_IDX_OFFSET (_Q_PENDING_OFFSET + _Q_PENDING_BITS)
> @@ -61,6 +73,7 @@ typedef struct qspinlock {
> #define _Q_TAIL_CPU_BITS (32 - _Q_TAIL_CPU_OFFSET)
> #define _Q_TAIL_CPU_MASK _Q_SET_MASK(TAIL_CPU)
>
> +#define _Q_TAIL_OFFSET _Q...
2014 May 07
0
[PATCH v10 03/19] qspinlock: Add pending bit
...ype ## _OFFSET)
@@ -48,7 +49,11 @@ typedef struct qspinlock {
#define _Q_LOCKED_BITS 8
#define _Q_LOCKED_MASK _Q_SET_MASK(LOCKED)
-#define _Q_TAIL_IDX_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
+#define _Q_PENDING_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
+#define _Q_PENDING_BITS 1
+#define _Q_PENDING_MASK _Q_SET_MASK(PENDING)
+
+#define _Q_TAIL_IDX_OFFSET (_Q_PENDING_OFFSET + _Q_PENDING_BITS)
#define _Q_TAIL_IDX_BITS 2
#define _Q_TAIL_IDX_MASK _Q_SET_MASK(TAIL_IDX)
@@ -57,5 +62,6 @@ typedef struct qspinlock {
#define _Q_TAIL_CPU_MASK _Q_SET_MASK(TAIL_CPU)
#define _Q_LOCKED_VAL (1U <<...
2015 Mar 16
0
[PATCH 3/9] qspinlock: Add pending bit
...ype ## _OFFSET)
@@ -45,7 +46,11 @@ typedef struct qspinlock {
#define _Q_LOCKED_BITS 8
#define _Q_LOCKED_MASK _Q_SET_MASK(LOCKED)
-#define _Q_TAIL_IDX_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
+#define _Q_PENDING_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
+#define _Q_PENDING_BITS 1
+#define _Q_PENDING_MASK _Q_SET_MASK(PENDING)
+
+#define _Q_TAIL_IDX_OFFSET (_Q_PENDING_OFFSET + _Q_PENDING_BITS)
#define _Q_TAIL_IDX_BITS 2
#define _Q_TAIL_IDX_MASK _Q_SET_MASK(TAIL_IDX)
@@ -54,5 +59,6 @@ typedef struct qspinlock {
#define _Q_TAIL_CPU_MASK _Q_SET_MASK(TAIL_CPU)
#define _Q_LOCKED_VAL (1U <<...
2014 Jul 07
0
[PATCH 05/11] qspinlock: Optimize for smaller NR_CPUS
...+0200, Paolo Bonzini wrote:
> Il 07/07/2014 16:35, Peter Zijlstra ha scritto:
> >On Wed, Jun 18, 2014 at 01:39:52PM +0200, Paolo Bonzini wrote:
> >>Il 15/06/2014 14:47, Peter Zijlstra ha scritto:
> >>>
> >>>- for (;;) {
> >>>- new = (val & ~_Q_PENDING_MASK) | _Q_LOCKED_VAL;
> >>>-
> >>>- old = atomic_cmpxchg(&lock->val, val, new);
> >>>- if (old == val)
> >>>- break;
> >>>-
> >>>- val = old;
> >>>- }
> >>>+ clear_pending_set_locked(lock, val);...
2014 May 14
2
[PATCH v10 03/19] qspinlock: Add pending bit
2014-05-14 19:00+0200, Peter Zijlstra:
> On Wed, May 14, 2014 at 06:51:24PM +0200, Radim Kr?m?? wrote:
> > Ok.
> > I've seen merit in pvqspinlock even with slightly slower first-waiter,
> > so I would have happily sacrificed those horrible branches.
> > (I prefer elegant to optimized code, but I can see why we want to be
> > strictly better than ticketlock.)
2014 May 14
2
[PATCH v10 03/19] qspinlock: Add pending bit
2014-05-14 19:00+0200, Peter Zijlstra:
> On Wed, May 14, 2014 at 06:51:24PM +0200, Radim Kr?m?? wrote:
> > Ok.
> > I've seen merit in pvqspinlock even with slightly slower first-waiter,
> > so I would have happily sacrificed those horrible branches.
> > (I prefer elegant to optimized code, but I can see why we want to be
> > strictly better than ticketlock.)
2014 Jun 15
28
[PATCH 00/11] qspinlock with paravirt support
Since Waiman seems incapable of doing simple things; here's my take on the
paravirt crap.
The first few patches are taken from Waiman's latest series, but the virt
support is completely new. Its primary aim is to not mess up the native code.
I've not stress tested it, but the virt and paravirt (kvm) cases boot on simple
smp guests. I've not done Xen, but the patch should be
2014 Jun 15
28
[PATCH 00/11] qspinlock with paravirt support
Since Waiman seems incapable of doing simple things; here's my take on the
paravirt crap.
The first few patches are taken from Waiman's latest series, but the virt
support is completely new. Its primary aim is to not mess up the native code.
I've not stress tested it, but the virt and paravirt (kvm) cases boot on simple
smp guests. I've not done Xen, but the patch should be
2014 Jun 17
5
[PATCH 03/11] qspinlock: Add pending bit
...typedef struct qspinlock {
> #define _Q_LOCKED_BITS 8
> #define _Q_LOCKED_MASK _Q_SET_MASK(LOCKED)
>
> -#define _Q_TAIL_IDX_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
> +#define _Q_PENDING_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
> +#define _Q_PENDING_BITS 1
> +#define _Q_PENDING_MASK _Q_SET_MASK(PENDING)
> +
> +#define _Q_TAIL_IDX_OFFSET (_Q_PENDING_OFFSET + _Q_PENDING_BITS)
> #define _Q_TAIL_IDX_BITS 2
> #define _Q_TAIL_IDX_MASK _Q_SET_MASK(TAIL_IDX)
>
> @@ -57,5 +62,6 @@ typedef struct qspinlock {
> #define _Q_TAIL_CPU_MASK _Q_SET_MASK(TAIL_CPU)
>...
2014 Jun 17
5
[PATCH 03/11] qspinlock: Add pending bit
...typedef struct qspinlock {
> #define _Q_LOCKED_BITS 8
> #define _Q_LOCKED_MASK _Q_SET_MASK(LOCKED)
>
> -#define _Q_TAIL_IDX_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
> +#define _Q_PENDING_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
> +#define _Q_PENDING_BITS 1
> +#define _Q_PENDING_MASK _Q_SET_MASK(PENDING)
> +
> +#define _Q_TAIL_IDX_OFFSET (_Q_PENDING_OFFSET + _Q_PENDING_BITS)
> #define _Q_TAIL_IDX_BITS 2
> #define _Q_TAIL_IDX_MASK _Q_SET_MASK(TAIL_IDX)
>
> @@ -57,5 +62,6 @@ typedef struct qspinlock {
> #define _Q_TAIL_CPU_MASK _Q_SET_MASK(TAIL_CPU)
>...